From 6b7f855f9e8c50be2cddcb3126e25f4986daa46e Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Tue, 26 Nov 2019 19:18:16 +0800
Subject: mir_opt_test - Add tests for SingleSetAndUse (includes one that
 caused bad codegen at one point)

---
 tools/mir_opt_test/parser.cpp                  | 36 ++++++++++++++++-
 tools/mir_opt_test/tests/single-set-and-use.rs | 53 ++++++++++++++++++++++++++
 2 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 tools/mir_opt_test/tests/single-set-and-use.rs

diff --git a/tools/mir_opt_test/parser.cpp b/tools/mir_opt_test/parser.cpp
index 72441db7..6d298d60 100644
--- a/tools/mir_opt_test/parser.cpp
+++ b/tools/mir_opt_test/parser.cpp
@@ -115,6 +115,11 @@ namespace {
         auto fcn_name = tok.istr();
         DEBUG("fn " << fcn_name);
 
+        if(consume_if(lex, TOK_LT) )
+        {
+            TODO(lex.point_span(), "Generic functions");
+        }
+
         // Arguments
         auto& args = fcn_decl.m_args;
         GET_CHECK_TOK(tok, lex, TOK_PAREN_OPEN);
@@ -187,7 +192,15 @@ namespace {
                 GET_CHECK_TOK(tok, lex, TOK_IDENT);
                 if( tok.istr() == "DROP" )
                 {
-                    TODO(lex.point_span(), "MIR statement - " << tok);
+                    auto slot = parse_lvalue(lex, val_name_map);
+                    if( consume_if(lex, TOK_RWORD_IF) )
+                    {
+                        TODO(lex.point_span(), "MIR statement - DROP if");
+                    }
+                    else
+                    {
+                        bb.statements.push_back(::MIR::Statement::make_Drop({ MIR::eDropKind::DEEP, mv$(slot), ~0u }));
+                    }
                 }
                 else if( tok.istr() == "ASM" )
                 {
@@ -207,10 +220,29 @@ namespace {
                     GET_TOK(tok, lex);
                     switch(tok.type())
                     {
-                    // Cnstant boolean
+                    // Constant boolean
                     case TOK_RWORD_TRUE:    src = MIR::Constant::make_Bool({true });   break;
                     case TOK_RWORD_FALSE:   src = MIR::Constant::make_Bool({false});   break;
 
+                    case TOK_PLUS:
+                    case TOK_DASH: {
+                        bool is_neg = (tok.type() == TOK_DASH);
+                        GET_TOK(tok, lex);
+                        switch(tok.type())
+                        {
+                        case TOK_INTEGER:
+                            TODO(lex.point_span(), "MIR assign - " << (is_neg ? "-" : "+") << tok.intval());
+                            //src = MIR::Constant::make_Int({ tok.intval(), ct });
+                        case TOK_FLOAT:
+                            TODO(lex.point_span(), "MIR assign - " << (is_neg ? "-" : "+") << tok.floatval());
+                            //src = MIR::Constant::make_Float({ tok.floatval(), ct });
+                        default:
+                            throw ParseError::Unexpected(lex, tok, { TOK_INTEGER, TOK_FLOAT });
+                        }
+                        } break;
+                    case TOK_INTEGER:
+                        TODO(lex.point_span(), "MIR assign - " << tok.intval());
+
                     case TOK_AMP:
                         if( consume_if(lex, TOK_RWORD_MOVE) )
                             src = MIR::RValue::make_Borrow({ 0, HIR::BorrowType::Owned, parse_lvalue(lex, val_name_map) });
diff --git a/tools/mir_opt_test/tests/single-set-and-use.rs b/tools/mir_opt_test/tests/single-set-and-use.rs
new file mode 100644
index 00000000..1cd5e542
--- /dev/null
+++ b/tools/mir_opt_test/tests/single-set-and-use.rs
@@ -0,0 +1,53 @@
+//
+// Tests for single-use-variable elimination
+//
+
+// Check forward movement of values
+#[test="simple_fwd_exp"]
+fn simple_fwd(a: i32) -> (i32,)
+{
+	let v: i32;
+	bb0: {
+		ASSIGN v = a;
+		ASSIGN retval = (v,);
+	} RETURN;
+}
+fn simple_fwd_exp(a: i32) -> (i32,)
+{
+	bb0: {
+		ASSIGN retval = (a,);
+	} RETURN;
+}
+
+// Reverse (upwards) movement
+#[test="simple_rev_exp"]
+fn simple_rev(a: i32) -> (i32,)
+{
+	let v: (i32,);
+	bb0: {
+		ASSIGN v = (a,);
+		ASSIGN retval = v;
+	} RETURN;
+}
+fn simple_rev_exp(a: i32) -> (i32,)
+{
+	bb0: {
+		ASSIGN retval = (a,);
+	} RETURN;
+}
+
+// Check that if there's a mutable borrow of the source, that the source isn't propagated forwards
+// - NOTE: This relies on the optimiser not being smart enough to move the `retval` construction up
+#[test="nomut"]
+fn nomut(a: i32) -> (i32,)
+{
+	let v: i32;
+	let ba: &mut i32;
+	bb0: {
+		ASSIGN v = a;
+		ASSIGN ba = &mut a;
+		//ASSIGN a* = +0;
+		ASSIGN retval = (v,);
+		DROP ba;
+	} RETURN;
+}
-- 
cgit v1.2.3